"With oil crisis memories starting to fade" Ford needed a V8 in the
Mustang II to return "performance to respectable levels." The engine
bay was re-engineered to accept the 302 cu in (4.9 L) V8 option for
the 1975 model year, with revised hood and header panel. The engine
was limited to a two-barrel carburetor and "net" 140 hp (104 kW; 142
PS). Since Ford's Mexican division never lost the V8, they assisted
in the modifications.

Testing by Road & Track "recorded zero to 96 km/h (60 mph) in 10.5
seconds, and a top speed of 171 km/h (106 mph)." The Mustang II's
302 cu in engine became Ford's first officially designated metric V8
Mustang; it was called the "5.0 L" even though its capacity was
4.942 L.

Other than the optional V8 engine, the car underwent minor changes
in 1975. The Ghia received opera windows and a padded vinyl
half-top. In mid-year, a 2.3 L "MPG" model was added, featuring a
catalytic converter and a 3.18:1 rear-axle ratio (standard was
3.40:1) to claim EPA-version economy estimates of 23 mpg‑US (10
L/100 km; 28 mpg‑imp) in the city and 34 mpg‑US (6.9 L/100 km; 41
mpg‑imp) on the highway. To underscore fuel efficiency, all base 2.3
L Mustang IIs were called MPG after 1975.

The Mustang II achieved record sales for 1975, making it the 9th
best selling Mustang of all time, with 199,199 sold.